Terminal structure and method of making the same



TERMINAL STRUCTURE AND METHOD OF MAKING THE SAME.

APPLICAIION FILED MAR.13, I918.

1 ,390,596'. Patented Sept- 13, 1921.

WITNESSES: I INVENTOR BY M ATTORNEY UNITED ST PATENT OFFI FRANK THORNTON, JR., 013 XNILKINSBURG, PENNSYLVANIA, *ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL VANIA.

TERMINAL STRUCTURE AN D METHOD OF MAKING THE SAME.

Application filed March 13, 1918.

To all whom. it In (13 concern:

Be it known that I. FRANK THORNTON, J r., a citizen of the United States, and a resident of W'ilkinsburg. in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Terminal Structures and Methods of Making the Same. of which the following is a specification.

Mvinvention relates to a terminal structure and the method of making the same,

brazed to a nickel-chromium resistance wire and. in certain instances. a narrow nichrome ribbon has been spot-welded to a terminal plate. However. these methods of securing wires to terminal members have not proved wholly satisfactory.

I have discovered that a very satisfactory union may be secured between a nickelchromium resistance wire and its terminal member by placing the wire between the terminal plate and a second plate and welding the two plates together by applying pressure and a heating electric current. thereby forming a clamp, with the nickel-chromium wire gripped between the two plates of the clamp.

The above and other objects and the novel features of the invention will be apparent from the following description taken in connection with the drawing, in which Figure 1 is a view illustrating a terminal structure embodying my invention, also showing a part of a resistance coil; Fig. 2 is a view illustrating a spot-welding method that is now employed to some extent; Fig. 3 is a view illustrating the method employed in forming the terminal structure; Fig. 4 is aview also illustrating a method embodying my invention, but showing another form of clamping plate that may be employed; Fig. 5 is a plan view of a part of the completed terminal structure, and Fig. 6 is a View in Specification of Letters .Patent.

Patented Sept. 13, 1921.

Serial No. 222,164.

cross-section of a finished terminal taken on the line VIVI of Fig. 1.

Referring to the drawing, Fig. 2 illustrates a method heretofore employed in spot-welding ribbons or wires 10 of nickelchromium alloy to a terminal plate 11 by pressure and heating electric current applied by the electrodes E and E. of spot-welding such alloys is due to two characteristics of this material, viz.: its high specific resistance causes an exceedingly rapid rise in temperature whilethe current is flowing through the wire, in case the operation is performed in the manner illustrated in Fig. 2, and, the surface resistance,

.due to the oxid on the nickel-chromium resistance material. causes local overheating and arching under these conditions, so that it is very difficult to avoid burning the nickel-chromium wire away if the current is allowed to pass through it.

In order to avoid the foregoing difliculties.

I form a clamp, as illustrated in Fig. 3, one member 12 of which constitutes a portion of the terminal plate or binding post and the other member 13 of which is so shapedas to provide flanges 131 at its edges to space the intermediate part from the opposing face of the terminal plate a sufficient distance to permit the insertion of the resistance conductor or conductors 14 in the said space. lVith the parts in the position shown in Fig. 3, heating electric current and pressure are simultaneously applied by the electrodes E and E whereby the two plates 12 and 13 are welded together to constitute a clamp for gripping the nickel-chromium wire. The flanges 131 are in electrical con tact with the terminal plate 12 so that, in performing the operation, little, if any of the heating current passes through the wire or wires 14.

As illustrated in Fig. 1, the terminal plate 12 constitutes one arm of a rightangle terminal member T. the other arm 15 of which is provided with the usual, or any preferred, binding screw 16, whereby The difficulty an electric-current-supply wire may be consecond clamping plate may have substantially the form indicated at 17 in Fig. 4, in which the face that-is adj acent the terminal plate 12 is grooved, as at 18, to receive the nickel-chromium conductor or conductors. The plate l7 also has greater areas of electrical'contact with the terminal plate 12 and, as in the former construction, the heating electric current applied by the electrodes and E passes through the areas of contact at the sides of the .wire or wires, causing the metal of, the clamps to'become heated to a welding temperature, and the pressure of the electrodes forces them together while they are in a soft condition. .The wires or conductors are thus clamped between the. welded plates and in intimate contact thereits terminal plate or member, the only requirement being that the metals comprising the parts of the terminal clamp shall be of a material that may be welded.

Numerous changes and applications that are within the spirit of my invention may occur to those skilled in the art and, therefore, I do not Wish my invention to be limited to the exact constructionghere disclosed but only by the scope of the appended claims. 7

I claim as my invention:

1. A terminal structure for'electric heating devices comprising two plates, one of which is provided with means for securing a line wire thereto, and a conductor of resistance material'having a portion at the end thereof clamped between said plates, said plates being electrically welded together along their edges. v

2. A terminal structure for electric heating devices comprising two plates, and a conductor composed of a nickel-chromium alloy having a portion of its end clamped between said plates, said plates being welded together along their edges on opposite sides of said conductor.

3. A terminal structure for electric heating devices comprising two plates, and a conductor of resistance material having a hook-shaped end clamped between said plates, said plates being welded together at points between and on the outer sides of the parts of said hook-shaped end.

In testimony whereof I have hereunto subscribed my name this 27th day of February 1918.

FRANK THORNTON, JR. 

